This invention relates to the marking and lighting of intermediate voltage powerlines which are less than 69,000 volts (phase to phase) and are primarily in the distribution range of 5,000 to 35,000 volts (phase to phase). Marking these phase lines with an illuminated spherical or elliptical obstruction marker decreases accidental contact by low flying aircraft, high profile water craft, construction, and industrial vehicles. The closest prior art is referenced by U.S. Pat. No. 5,001,402 and U.S. Pat. No. 4,839,567 for high voltage lines. These are incorporated herein by reference. This invention uses a smaller physical size than U.S. Pat. No. 5,001,402 and U.S. Pat. No. 4,839,567 in order to maintain safe distances between the phase lines and the exterior of the invention. In using a smaller physical size, below FAA recommended spherical diameters for obstruction marking of power lines, major changes must be made to achieve a 2000' conspicuity. A different size or shape of the unit must be used on intermediate voltage lines because of line spacing. In prior art, the spherical shape was used to put as much of the capacative surface away from the electrical line as possible to give the greatest possible potential difference between the shell and the line. Since the unit outlined in the prior art has a greater diameter, the capacitive surface area is much greater and consequently, greater electrical potential difference and greater circuit current exists. This invention must utilize a smaller capacitive area and coupled with the lower operational voltages, usually in the range of 7,900 volts to 16,000 volts (phase to ground), the unit must operate at a significant power reduction to activate the gas filled lamp. Additional capacitive area is attained by elongating the unit without sacrificing electrical phasing safety margins. We have found experimentally, using light enhancers, that a conspicuity of 2,000 feet may be obtained using a gas filled tube of approximately 54" in length, 5 mm in diameter, and with a internal pressure of 19 mm. In prior art, two 120" tubes, 10 mm in diameter and with 10 mm pressure was used. The smaller tube needs to be charged with much higher pressure (over 10 mm) to at reduce inherent electrical resistance and the smaller tubing restricts the ionization electron column to give greater lamp intensity per inch. With the decrease in capacitive relationships in the unit, the tubes may be placed in closer proximity to each other to create a brighter concentrated light without excess heat or capacitive shorting. With the concentration of the light, additional reflectors must be used for the dispersion of the light to increase visibility below or above the unit. Prior art utilized two sets of 10 mm tubing at 10-12 mm pressure in lamp tubes 120" in length to handle a variety of high voltages, reduce heat as a debilitating factor to lamp life and achieve visibility of the device that exceeds 4000'. Two lamps were used to give directional light by placing each lamp about the hemisphere with the lamping center 180 degrees from each other. Since the smaller conductors are primarily used in the construction of these intermediate voltage distribution lines, as compared with high voltage lines, rotational problems occur for single source lighting. Reflectors and prismatic film were used to concentrate the effective beam spread to give greater visibility to the areas that were suspect to vehicles approaching the installed unit.
We have found that a set of inductors will, through counter electromotive force (CEMF), induce a staggered discharge of the circuit and sustain more ionization in the lamp. This CEMF occurs as a reaction to changes in the voltage and current. This enhances the uniformity of the illumination. Prior art had no use for this type of staggered discharge because of the higher voltage and current that normally discharged from the larger capacitor. These coils, by weight and placement, are also used as a counter balance to reduce the rotational effects of the device when it is installed where the power line runs through the center of the unit. Additional attachment procedures are explained in the drawings; these include a gimbaled device and a device hung from the power line using a flexible cable.
In summary, the subject invention must use a specific physical form to maximize the operation of a smaller concentrated neon gas lamp because of voltage and dimensional restrictions and must use light dispersion techniques to enhance conspicuity to provide the necessary 2000'-2500' visibility.